Implementation of a solar-assisted hybrid sulfur cycle for hydrogen and oxygen production in the Chilean copper industry

Copper is essential to the energy transition due to its exceptional electrical and thermal conductivity, making it critical for power generation, transmission, storage, and renewable energy systems. In 2023, Chile accounted for roughly 25% of global copper production, a leading position driven by mining and smelting activities that are highly energy-intensive, consuming nearly 37% of national electricity and 20% of heat demand, primarily for comminution, electro-refining, smelting, and converting processes that also require substantial fuel and oxygen inputs. Such high energy use, combined with the need for both fuel and oxygen in pyrometallurgical operations, highlights the need for alternative pathways capable of supplying these inputs while reducing fossil fuel dependence. In this regard, this study assesses the techno-economic feasibility of a Hybrid Sulfur (HyS) cycle for the co-production of hydrogen (H 2 ) and oxygen (O 2 ). The techno-economic analysis focuses on a copper smelting facility in northern Chile with an annual output of 100 kt. Results indicate that the HyS cycle can achieve lower overall energy consumption than Proton Exchange Membrane (PEM) electrolysis when two conditions are present: (i) the electricity demand of PEM exceeds 50 kWh ele /kg H2 , and (ii) the HyS process operates under favorable conditions, characterized by high H 2 SO 4 decomposition temperatures ( ∼ 1400 K), highly concentrated H 2 SO 4 feeds ( > 75 wt%) at the decomposition inlet, and highly effective heat recovery. Based on conservative electrical and fuel prices and a limited heat recovery the estimated Levelized Cost of Hydrogen (LCOH) is 5.74 ± 1.04 €/kg H2 . PEM and alkaline electrolysis are mature and widely deployed technologies for green hydrogen production; however, their economic feasibility remains highly dependent on electricity prices, which poses challenges in regions without stable access to low-cost electricity. In contrast, the HyS cycle relies predominantly on thermal energy, particularly in the sulfuric acid decomposition section, and is therefore less sensitive to electricity price volatility. This characteristic makes the HyS cycle a promising option for the co-production of hydrogen and oxygen in Chile’s pyrometallurgical copper industry, contributing to decarbonization. Nevertheless, challenges related to scale-up and material durability remain. • The proposed HyS cycle shows significant potential for the simultaneous production of oxygen and hydrogen to meet energy needs in Chile’s copper industry. • Competitiveness with PEM electrolysis requires HyS operation at high decomposition temperatures ( ∼ 1400 K), highly concentrated H 2 SO 4 feeds ( > 75 wt%), and efficient heat recovery. • The estimated Levelized Cost of Hydrogen (LCOH) is 5.74 ± 1.04 €/kg H 2 under conservative assumptions for electricity, fuel prices, and limited heat recovery. • By relying predominantly on thermal energy, the HyS cycle complements PEM electrolysis and provides a robust pathway for hydrogen–oxygen co-production in Chile’s copper industry.